运城MS4.4地震前山西中南部重力场变化特征

基于长基线标定和绝对点实测标定得到的重力仪一次项格值系数，对山西中南部测网2014～2016年流动重力数据进行经典平差计算，得到运城MS4.4地震前0.5 a尺度的重力场变化图像。结果表明，运城MS4.4地震前，重力场经历了区域性重力变化-局部重力变化明显-反向重力变化-发震的演化过程。

Gravity Changes before the Yuncheng MS4.4 Earthquake in South-Central Shanxi

Based on the grid value of the coefficient term of relative gravimeter resolved from long baseline and absolute point calibration, we calculate mobile gravity data from 2014 to 2016 in south-central Shanxi province network using the classical adjustment method. Then we get the images of gravity field change in 0.5 a scale. It turns out that the evolution of gravitational field occurs in three stages, which are the regional negative gravity anomaly,the local gravity anomaly and the earthquake occurrence, in the study region before the Yuncheng earthquake.